What’s It All About Then, Davey?

In the past I’ve been critical of people writing over-long documents on Accessibility, in my critique of WCAG 2.0 and my beginners guide to the Disability Equality Duty. Now, a 218 page word document on “The Effectiveness of the Web Accessibility Audit as a Motivational and Educational Tool in Inclusive Web Design” has landed on my lap and I’m enthusiastic about it, despite its wordiness and use of academic jargon. This isn’t a case of double-standards, this is because this document is intended primarily for academic consumption, having been written as a PhD thesis, and the author David Sloan was kind enough to send me a copy when I asked, so it’s my own responsibility to extract the meaning from it.

Why did I ask? Well, he’d mentioned in conversation he was writing it and I’d enjoyed debating accessibility with him in other documents he’s written. I don’t normally agree with him on everything — in fact I’ve been critical a few times, but we’re on good terms because we both appreciate where each other is coming from, and accept that it’s possible to have differences of opinion without them descending into arguments and slanging matches. I find it interesting that we’re looking in the same direction but from two different starting points: Academia in David’s case, and Over By The Quiz Machine In The Pub in my case.

As an aside, it was fascinating to note the sheer number of papers on accessibility that were referenced in the bibliography that represent research into accessibility that I — and I suspect a majority of other developers, even amongst those with a passion for accessibility — was entirely unaware of. It’s frankly appalling that there’s so much research into accessibility that is not widely known to and is not available to the development community. The academic world need to make a decision here: do they want their research to stay locked away in their ivory towers or are they prepared to start doing some stuff in Plain English — summaries of their findings for instance — and actually telling people outside The Land Of Academia about them? David’s the only person I know who’s really done this so I don’t mind looking at his like this but I’m buggered if I’ll do the lot of ‘em…

Anyway, David, Dave, Davey to his mates (but probably not me after that) seems a jolly nice chap and I hope his PhD goes very well.

One thing I noticed that I didn’t like about the document was that it was right-justified, meaning it’s more difficult for users with dyslexia to read it. That’s not necessarily David’s fault; it may be that David is perfectly aware of this but for some reason PhD submissions must be right justified. If this is the case however, I’d like to know what the justification is for insisting that documents are published in such a way as to make them more difficult to read for users with dyslexia.

Anyway, on to the document — although I’ll warn you now, I tend to get sidetracked … like you’d not already noticed. Mmmmn, nice shoes.

Introduction

In the introduction, after providing a brief introduction as to what web accessibility is (we’ll come to that later), he points out that it’s something not everyone’s aware of:

awareness of accessibility issues appears deficient even in what can be considered the professional Web design industryDavid Sloan

This is sadly true but is something I personally keep forgetting because I blog about standards and accessibility, I’m personally strongly in favour of equality of opportunity regardless of ethnicity, disability, gender, sexual preference, religion, and/or favourite amphibian. I read forums (fora?) on accessibility and standards, and I’m friends with a number of bloggers who are themselves keen on standards and accessibility. Well, at least they keep banging on, and on, about it. So it’s only natural that in my “comfort zone”, I’m aware that people see accessibility and standards as something important.

David also reminds us that not everyone who produces web content is a web professional:

As a publishing medium, it enables anyone with the desire — or responsibility — to create and publish Web content to do so without the need to undergo formal training, reach a specific level of expertise or accreditation, or engage professionals to carry out the task on their behalf.David Sloan

…and therefore we can’t necessarily expect everyone publishing web content to be aware of the importance of accessibility.

He then goes on to cover the importance of accessibility in some detail, which I’m not going to look at here because for a start his thesis is 218 pages long, so if I go into it in any great depth, we’ll be here all week, and also because what his thesis is actually about is:

The Effectiveness of the Web Accessibility Audit as a Motiviational and Educational Tool in Inclusive Web Design

…but that’s only one of the things I want to look at.

Accessibility and Universality

It seems that David shares my belief that accessibility is pretty much making your site “accessible to all”, meaning that you need to include considerations such as varied user agents, screen resolutions and so on.

As alluded to in the technical and financial factors noted above, Web accessibility is not limited to supporting people who may fall within a conventional notion of “disability” … for example a hand held device with small, monochrome display effectively introducing significant visual impairmentDavid Sloan

This is also how I think of the term “accessibility”, something I have in common with many others, including Tommy Olsson, Mike Cherim and Roger Johansson.

However, many people believe the term should be used only in relation to disability:

Web accessibility means that people with disabilities can perceive, understand, navigate, and interact with the WebWAI

The much respected Joe Clark also seems to share this view:

The goal of the accessibility advocate is to improve accessibility for people with disabilities, periodJoe Clark

Basically then, there are two camps:

Camp 1

Accessibility means accessible to user with disabilities plus able to be used by different browsers, devices and screen resolutions plus being sufficiently usable

Camp 2

Accessibility means accessible to users with disabilities plus being sufficiently usable

Note that I say sufficiently usable because I think both camps believe that if something is sufficiently difficult to use this becomes a significant barrier to access. Indeed, David finds a quote for exactly this point:

…it is rarely useful to differentiate between accessibility and usability…the distinction between accessibility and usability is especially hard to define when considering cognitive and language abilitiesLawton Henry

…although,no doubt some people would disagree.

I’m not seeking to indicate that any particular view is correct, merely that people may mean different things when they talk about accessibility, and you should be aware of this. As regards comments on this article, I don’t want to hear which you believe is right, and comments to this effect will be deleted/redacted. There is more than one definition used by different people, and like all definitions, people can get quite worked up and/or argumentative about it. So if you want to fight about it, take it outside, okay?

Accessibility As A Threat

During the requirements gathering stage of the project, it became apparent that the subject of accessibility was a highly emotive one amongst media producers, some of many years’ experience. Reactions related to the significant impact accessibility might have on their working practices, and in some cases there was the perception that, in coming under an “accessibility microscope”, the quality, legality and ethical value of their work was in questionDavid Sloan

To be honest, this reaction is understandable, particularly considering that if you’re undergoing an accessibility audit, the quality, legality and ethical value of your work is being called into question (or at least assessed). When I know anyone is going to critically assess any work I’ve written I immediately worry about what they’re going to find. On the one hand, I do want the opportunity to produce the best work I possibly can, but on the other hand when you’re being critically assessed you’ve got to be able to justify pretty much every decision you’ve made, which can be very hard work, even if you can. I guess it’s a bit like having a PhD accepted…?

Accessibility Standards Are The Problem

Ooh, this could be controversial bit. David — unless I’ve misunderstood him — believes that while accessibility guidelines, such as those laid down by the W3C are very useful in demonstrating how sites can be made accessible, guidelines by their very nature bring their own problems.

They can cause accessibility to be seen as yes/no state rather than a continuum:

…then implies a binary state of either “WCAG-conformant and accessible to all disabled people” or “not WCAG-conformant and therefore accessible to no disabled people”David Sloan

He also noted that:

An investigation of museum Web sites in the UK showed that some Web sites analysed to have a high level of conformance to WCAG were also found to be “unusable by disabled people”David Sloan

Now David wasn’t trying to make the case that accessibility standards are a bad thing, but what he was doing is illustrating that accessibility guidelines in themselves don’t make sites accessible.

What makes sites accessible, or usable, is good design and an understanding of the needs of your potential audience. In fact, David makes pretty much this point himself, referring to the “Eureka moment” of true understanding of accessibility:

there is a need for Web authors to reach a point where an awareness of theory and acquiring of technical skills becomes crystallised by an understanding of how people with different disabilities interact with Web content, the range of skills, attitudes and coping strategies that may be adopted, and the effect that design decisions can have on this interaction.David Sloan

Carrying Out Accessibility Evaluations

He goes into great detail about how evaluations may be carried out, and how they frequently are carried out in practice, commenting on the proportion of people involving manual evaluation, the proportion claiming to always include disabled user evaluations and so on.

He also highlights the difficulties in carrying out evaluations with disabled users: you need a pool of disabled users willing to carry out your tests, and you need to make sure that they are a reasonably representative group: a group with expert IT skills might not encounter problems; groups with less self-esteem might believe the problems are their own fault rather than that of the design and so not report them, and the fact that paying disabled people for their time may affect their entitlement to state benefits and so discourage them from helping in the first place.

Frankly, it’s not always possible. My personal site isn’t tested by anyone with a disability and for a lot of small sites it might not be practical — this is where following the published guidelines and having an understanding of good practice comes in handy. For larger sites however, if you can afford testing, it is invaluable.

After all:

nondisabled people are not very good at pretending to be disabledJoe Clark

Although bizarrely enough, you do get some people who do pretend: the ouch podcast no 5 (podcast transcription) highlighted someone known as “Shy” — for obvious reasons — from the USA who pretends that she is deaf, including wearing a hearing aid with custom ear moulds even though she’s not actually deaf. There’s not much I can really say to this, other than “it takes all sorts, doesn’t it?”

Reporting Accessibility Evaluations

It’s all very well carrying out an accessibility audit, but the only real benefit of this will come if it helps to make the site itself more accessible — and ideally help the designers to experience David’s “Eureka Moment” so that they have a better understanding of the needs of disabled users and future developments will be more accessible in the first place.

You therefore need to be sure that you’re not going to antagonise the creators of the site: you need to carefully construct your report so that your message comes through clearly but constructively — and this applies doubly if your report on their accessibility failings was unsolicited!

Bartlett […] identified a tendency amongst accessibility advocates to report accessibility barriers through an unsolicited and hostile approach to a Web site owner, which may lead to the effect of antagonising the site owners.David Sloan

I know a lot of accessibility advocates — probably including me as well — because although I try to be fair, by nature I’m an argumentative bugger — have fallen foul of this before, calling “foul” as soon as they see something bad, rather than stopping to explain patiently to the relevant site owner why they haven’t achieved WCAG 1.0 Triple-A compliance, discovered the Philosopher’s stone and found a way to transform base metals into gold. This attitude can be understandable, given that there are no doubt snake oil salesmen out there, trying to make a quick buck on the promise of accessibility, but that doesn’t mean this attitude is right. Well said, David and Kynn, I’ll try and be a good boy from now on.

Purpose of the Thesis

Which brings us to the “meat” of the document. David wants to find out:

how to effectively produce a Web site accessibility report that achieves the dual aims of:

1. accurately reporting accessibility barriers present in a Web site and how to overcome them; and
2. enlightening the commissioning organisation and individual readers as to how disabled people interact with the site and therefore how best information, functionality and intended experience of the site can be provided to people with specific impairments.

David Sloan

In order to do this, they have to evaluate several sites for accessibility, produce the accessibility evaluations and then step back to measure the effectiveness of the accessibility audit in terms of education and motivation. Frankly, rather him than me. It’s a noble goal, but it looks far too much like hard bloody work for my liking. [Note: upon further reading it became apparent that much of the initial audits had already been carried out, reducing the workload somewhat.]

The Accessibility Audits

They found a lot of problems that were common across many of the sites:

1. Lack of consistent and efficient navigational systems, including inconsistent provision of navigation bars, lack of internal page links, and link text that did not clearly indicate the destination page;
2. HTML code that did not validate to recognised standards;
3. Limited, or no, ability to change visual appearance;
4. Poor information layout, including excess content on pages, and inappropriate use of lists.

David Sloan

I’m not convinced that a limited ability to change the visual appearance is necessarily an accessibility barrier if the visual appearance is clear enough in the first place, and the user can resize the text via their browsers. After all, that’s the job of the user-agent, is it not? See, I told you I didn’t always agree with him. Nevertheless, I’ll let this one slide for now…

What did this actually mean?

One interesting outcome of this evaluation programme was the realisation that there was often a discrepancy between the priority level of a specific unmet WCAG checkpoint and the level of impact on disabled evaluators of the unmet checkpointDavid Sloan

Now that’s interesting. It could just be that David’s testers placed a different priority on things than the W3C’s testers did in the first place, or it could be that there were more reasons than simply the impact of the changes for why things were assigned to a particular priority level, although WCAG 1.0 does pretty much indicate that’s the only reason. Another possibility is that technological developments between 1999 and now have meant that the relative impact of different barriers to accessibility has changed significantly between then and now. Maybe that’s why we need WCAG 2. Done properly, of course…

The feedback from the site administrators showed that on the whole there was a positive response to the fact that the audit was conducted, they were neutral as to whether or not they agreed with the findings of the audit, and the recommendations were slightly difficult to follow. Is this a case of people thinking “thanks for the audit mate, but I was right in the first place?”

One interesting comment was that it’s maybe only possible for certain site owners to go so far in implementing changes:

It was also noted by some respondents that the issue of third party provision of Web site content was a significant barrier to implementing accessibility improvements across the entire subject siteDavid Sloan

Obviously, changes to a third party site will incur additional development costs, and this is why you should always refer to our good friend PAS 78 when commissioning sites. This will help you to ensure that the sites you commission are accessible in the first place, but beware, it’s not a ticky-box, you can’t just say “it must comply with PAS78!” and leave it at that. PAS 78 isn’t a set of instructions for the site developers to follow, it’s a set of instructions for the site commissioners to follow. I never said there were any easy answers.

And then, some time after the initial audits had been completed, there was obviously a follow-up piece of work to see what had changed since the initial audit.

The Impacts of The Audits

Well, obviously we’d all hope the sites reviewed had taken on board all of the good advice — even if they’d ignored the bits they’d disagreed with, and had found the rest slightly difficult to follow. Unfortunately it turns out there was actually quite a high proportion of “thanks for the audit mate, but I was right in the first place” — of the 11 sites audited:

• One site had implemented a small number of changes suggested in the audit, but retained the appearance and structure;
• 6 sites had undergone extensive redesign;
• 4 sites appeared not to have changed at all in terms of accessibility.
• For the sites that had undergone extensive redesign, a brief inspection indicated that all sites had eliminated most of the accessibility problems highlighted in the site audit

David Sloan

Well, at least the majority of the sites had taken it on board quite extensively, and that the audit reports had been of some practical use, at least for the sites which had bothered to take some notice of them.

What now? Well, in the interests of scientific endeavour, the experiments get repeated, taking into account the lessons learned from the first set, that’s what.

The Second Set Of Audits

David goes into great detail here about how the audits are actually carried out, the methodology used and so on. It’s certainly a very thorough audit, perhaps the most thorough I’ve ever heard described, with up to seven separate stages (six evaluation stages plus a recommendation stage). It’s probably impossible for an audit of this nature to uncover every potential problem a site will have, but the methodology David describes (including such things as a task-based approach based on the principles of the UK Disability Discrimination Act) should have a damn good chance — and better than most — of uncovering the barriers.

The audit recommendations this time were assessed according to the impact they would have, and broken down as follows:

1. Recommendations that should be followed as soon as possible.
2. Recommendations that should ideally be followed in time, but are of less significance than the higher priority tasks, or may require significant effort to implement.
3. Examples of good practice, and which should be continued.

As well as indicating what should be done in each case, the following information was also provided:

1. a rationale justifying why the recommendation should be applied;
2. example(s) of where the recommendation should be applied;
3. any examples of where the recommendation has already been followed in the site.

David Sloan

I’ve not seen one of these accessibility audits, but I imagine it would be particularly useful to someone who had a limited knowledge of accessibility issues as it’s not just telling them what to do, and how to do it, but why to do it as well: he’s after that “Eureka moment” again, isn’t he?

The audit reports may be quite detailed, and take a bit of reading:

An audit report of a site with significant accessibility barriers will by its nature include a longer Findings section and a greater number of Recommendations for improving the site’s accessibility than would a site with a higher level of accessibility. The length of DMAG Web accessibility audit reports therefore have ranged from 50 to 90 pagesDavid Sloan

…but in order to provide the full information that’s necessary, this length of report is probably warranted.

Also, it was intriguing to note the browser used for the primary evaluations:

Significantly, the Mozilla Firefox browser, with the Web Developer ToolBar extension installed, replaced Internet Explorer as the primary evaluation browser, the toolbar allowing more efficient evaluation of issues such as performance with style sheets and JavaScript disabled.David Sloan

While I’m somewhat of a fan of the Firefox browser, and indeed of the toolbar noted, I must note that I’ve had equal success using the Web Accessibility Toolbar with both Internet Explorer and Opera, as part of my work evaluating sites for Accessites.

Before looking at the results, David also comments on other evaluations which have been carried out in the past, in order to compare the DMAG methodology they use with methods others use. He points out that the majority of evaluations have involved some form of automated test — some relying solely on this — and highlighting the difference between an accessibility audit that someone has requested and paid for and one that has been carried out as part of some form of unsolicited survey:

By their nature, these accessibility evaluations are most likely to have been actively requested by organisations seeking to improve accessibility. Therefore it is also assumed that recommendations arising from the evaluation are more likely to be acted upon than the findings of an uninvited large scale surveys.David Sloan

Evaluation of Audit Impacts

David clarifies that the evaluation of the effectiveness of the audit impacts was carried out as a follow up to a sample of 14 audits that DMAG had carried out over several years as a commercial service (and therefore you would have expected to have been more likely to act upon the findings). Data was collected by means of questionnaire (with the obvious understanding that some of those originally involved may now have left), and also by re-reviewing the websites in order to:

…identify the degree to which the audit recipients had:

1. Taken the appropriate steps to improve the accessibility of the subject Web site; and
2. Shown a public commitment to promoting Web accessibility throughout the organisation.

David Sloan

One of the questions given in the questionnaire was that respondents were asked to rate their own accessibility knowledge on a scale of 1 (knows nothing) to 7 (expert). Apart from the question that it’s obviously difficult to assess yourself on such a measure: I’d give myself a 5, or maybe a 6 as I’m aware of people who know a lot more than me, but I know some people would give me a 7. On the other hand, some people would probably only give me a 4. Perhaps it’s time to use Joe Clark’s Levels Of Accessibility Knowledge as an official measure?

The assessment of the questionnaire results in comparison to perceived accessibility knowledge did throw up some interesting results, however. I couldn’t be bothered to check whether they were statistically significant or not, so I’m quite prepared to take David’s word for it:

At the 95% confidence level, a significant negative correlation was indeed found between expertise in accessibility and level of agreement with […] “The audit made me more aware of the importance of the issue of Web site accessibility to disabled people”

Additionally, a negative correlation approaching significance was found between expertise in accessibility and level of agreement with […] “The audit made me more aware of the problems that disabled people can encounter when accessing Web sites”

David Lawson

In other words, the more sure you already are of your own knowledge, the less reading an audit report is going to do to change your opinion of the importance of accessibility, and your overall knowledge of problems relating to accessibility barriers. This seems perfectly reasonable to me, to be honest — if you consider yourself an expert in web accessibility, you’ve obviously taken some time to learn about it, and you’re not likely to have done that unless you already thought it was important, are you? And if you are an expert, chances are you’ve already got at least a reasonable grounding in what the accessibility barriers are, whereas if you’re newer to the subject, you’ve got more to learn and so it’s more likely that your knowledge and attitudes will change.

I would however be interested to see if a larger survey could uncover anything statistically significant between levels of accessibility knowledge and other statements. Do self-proclaimed experts rest on their laurels, content they know it all already, or are they always seeking to learn more? In my mind at least, the key thing to assess the impact of an accessibility audit is the effect it has on the relevant site, and this is what David looks at next:

the cumulative performance of each subject site, with respect to the level and quality of repairs made following the audit delivery, was graded on a five point scale: 4 (Excellent), 3 (Good), 2 (Adequate), 1 (Poor) and 0 (Very Poor).David Sloan

There turned out to be quite an even split — 3 graded as excellent, 2 each at Good and Adequate, and 3 again at Poor, although all of the sites managed to avoid the Very Poor grade for quality of repairs made. Some of the sites had made very significant changes, including some significant innovations of their own – one site had produced:

The University Accessibility Standard: this page specified a minimum level of accessibility – with which “each page published by or hosted by the University” should comply. It also mandates a published accessibility statement for all university Web sites.

Unsurprisingly enough, it turned out that of the seven stages making up the evaluation, the audit recommendations were seen as the most useful to the recipient (69% of cases). But is this indicative that users are ignoring/skimming the rest of the document and just jumping to “what do I have to do?”

However, recipients who have the perception that the crux of the audit document is the list of actions to be carried out may give less attention to, or even ignore, the rich narrative information presented prior to the recommendations. The likelihood that a “Eureka moment” may occur through reading a set of recommendations is expected to be low, in comparison to exposure to a real-world account of a disabled person interacting with a Web site.

David Sloan

As an aside, AbilityNet and FramFab produced some fantastic videos which were shown during Robin Christopherson’s talk at the @media 2006 conference which in my opinion would be of fantastic benefit if you’re trying to help someone hit a “Eureka moment” and don’t have the time or money to do actual testing with users with disabilities. The drawback is of course that I don’t believe that these videos are yet publicly available: but if you do get the opportunity to see them, I would certainly recommend it as they were of excellent quality.

Whereas the users who had rated the User Evaluations with Disabled People stage highly give a different flavour, saying that they felt that IT personnel cometimes don’t appreciate what the issues are as they are “too close” to the subject.

As David identifies, this shows an apparent lack of confidence that developers and/or non-disabled auditors would be able to identify all the problems. In some cases the very nature of the external audit was seen as beneficial:

there was evidence to indicate that, for many respondents, one important attribute of the audit was that it was an externally produced, independent report on the subject site, and therefore “politically neutral”David Sloan

This is a very revealing statement, and yet not quite revealing enough. It reveals that something you’ve paid for tends to get valued more than unsolicited free “advice” from a self-proclaimed in-house “expert” (but that’s human nature), so if you spend X amount on an external audit, you may give more credence to that than to someone in-house carping on about it again (regardless of which one is actually more correct). What is doesn’t reveal is what specifically the “political neutrality” refers to: is it related to inter-departmental debates or does it give more clout with the “man at the top”?

Either way, it’s a shame. I understand the value what you pay for thing, but I work in the public sector — and while I don’t necessarily agree with everyone all the time — everyone I come into contact with in my organisation or similar organisations seems to understand the importance of accessibility, and so we’re certainly all pulling in the same direction.

7 of the sites audited had provided a dedicated accessibility page or section since they were first auditedDavid Sloan

However, there was also some evidence that accessibility was being taken at face value – one of the sites which showed little improvement since the initial audit commented that:

In both cases, the software houses involved went on to modify the sites to comply with the requirements.

As David states:

This finding is of some concern. It may be seen as a sign that, despite best efforts, the audit content did not adequately explain the work required to implement the recommendation. Alternatively, it is possible that the respondent was not in a position to confirm that claimed improvements had in fact been satisfactorily made, when evidence indicates that they had not.David Sloan

I’m presuming that by the last point he means that the respondent has either assumed that the sites has undergone the required changes, or has been told that the site has undergone the required changes, and has simply taken this at face value, rather than carrying out any checks. This brings me back to PAS 78 again: accessibility is not a ticky box. It’s a way of life; like I’ve said before — probably more coherently — accessibility is like a kind of a Zen thing, yeah?. You can only ensure accessibility by building it into each and every one of your processes, not by simply asking a supplier/designer “is your site Double-A compliant?”.

A final explanation may be that for some Web developers, accessibility remains of lower priority than competing objectives.David Sloan

Hmm. Well, my rules of site design are as follows:

1. Get the damn thing to work for you
2. Get the damn thing to work for everyone
3. Get it to look nice

Of course, I come from a coding/developer background, rather than a designer background — Tommy Olsson would probably term me a structural designer.

These rules are quite simple though. Firstly, make sure your site can do what you want it to do. Secondly, make sure everyone can make your site do these things (“accessible to all” — but let’s not get into the whole definitions thing again). Finally, make it look nice. If it looks nice at the expense of one of the first two, it’s a waste of time: you’ve got a nice looking site that doesn’t work properly. I’m not saying the design isn’t important: I’m just saying the function is more important.

David presumably felt that the study didn’t answer all his questions, owing to the lack of a control group it would be quite difficult to tell exactly what improvements in knowledge and site design and came up with what looks like a pretty impressive methodology for anyone wishing to take the study further:

1. Carry out an accessibility review of a Web site, using the DMAG methodology […]
2. Provide an audit report consisting only of recommendations to a group of n developers.
3. Provide an audit report consisting of evaluation stage findings but with no recommendations to another group of n developers.
4. Ask each developer to improve the accessibility of the Web site that was the subject of the audit.
5. Assess the quality of changes made by each developer.
6. Repeat Steps 1, 4 and 5 after a period of time, using a different subject Web site (this time developers are not provided with an audit).
7. Assess the quality of changes made by each developer.
8. For each developer, compare the results of Step 5 with Step 7.
9. Compare performance of the two evaluator groups.

David Sloan

Summary

I’ll let David sum it up for you, as he does it quite concisely:

The study assessed the Web accessibility audits produced using the DMAG methodology and found evidence that they:

1. accurately reported accessibility barriers present in a Web site and described how to overcome them;
2. improved the understanding of commissioning organisation and individual readers as to how disabled people interact with the site, and how information, functionality and intended experience of the site can best be provided to people with specific impairments.

[…]

There is clear evidence that individual recipients of the audits have valued its contribution to their awareness and understanding; there is also clear evidence of action being taken by commissioning organisations after the audit was received.

David Sloan

So there you have it. Accessibility audits won’t just make your site more accessible, they’ll increase your understanding of the needs of disabled users, and this information will help you with future developments.

Of course, you don’t just have to use DMAG: RNIB carry out paid for audits (including one with AbilityNet); as do the Shaw Trust; and various other companies also offer them as a commercial service.

Or I can summarise it even more succinctly: accessibility audits are useful. If you can afford one, and you’re willing to listen and learn from one, and actually take whatever actions are needed, then go get one.